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22 views

Fitting multiple normal distributions to sample data

I have a data set of (time, action)-tuples. Actions are typically performed at approximately the same times every day, and depending on what the action is it may be done multiple times per day. If I ...
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1answer
76 views

Fitted Beta distribution always holds water. Can I force it not to?

I am trying to fit a beta distribution to election forecast data. The ultimate purpose is determining with what probability the election will be decided by one vote (more on this here). My data is as ...
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0answers
13 views

geeglm not recognizing clusters

I am fitting a geeglm model and it is not recognizing the clustering. my model is ...
1
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0answers
46 views

How to determine if GLM quadratic term should be set up orthogonal or non-orthogonal

I am setting up a GLM in R where I have only one predictor variable and its quadratic form. I understand that in R I have 2 options. ...
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0answers
25 views

Do we fit this time series data with time series model or spline?

Basically, I have the following data with the number of item A on the vertical axis and the time on the horizontal axis (from 1st hour to the 24th hour). I don't have much experience in fitting a ...
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0answers
25 views

Align two datasets in Python

I want to develop some python code to align datasets obtained by different instruments recording the same event. As an example, say I have two sets of measurements: ...
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0answers
38 views

How do I verify whether a population distribution is a power-law? [duplicate]

given a population of discrete values (not a sample), is there any way to check whether the distribution is a power-law, and with what parameters? Of course I can just plot the distribution and see ...
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0answers
22 views

Least-squares fitting with only optimum features, after Lasso - valid?

Using Lasso reduces the coefficients of features of a model, reducing some to zero, and thereby performing feature selection. The number of features depends on the value of $\alpha$ aka $\lambda$. In ...
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0answers
18 views

Least Squares Regression - Error [duplicate]

In standard least squares regression, we find constants $\beta_1$ and $\beta_2$ such that the square of the average error, $\epsilon = y_i - (\beta_1 + \beta_2x_i)$, is minimized, and so the 'line of ...
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0answers
37 views

How to run an nls model in R to generate output parameters for independent categories?

I would like to get help on the following code: library(nlme) funct1 <- function(scale1,a){ exp((scale1 - 2)/a) } ...
0
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1answer
34 views

How to calculate the probability of a datapoint fitting in a known distribution

I have a set of samples, each with a concentration for element A which is shown on a log scale on X-axis on the histogram below. The number of samples with the same concentration is shown on Y-axis. ...
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0answers
12 views

How to fit raw signal

I think this is simple, but somehow it's not working. I'm trying to fit my raw data so that basically I end up with beautiful 1 peak. I tried butterworth filtering, Gaussian fitting, a combination of ...
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0answers
22 views

How should I fit this data?

I have a dataset: ...
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2answers
83 views

Power law fitting of data with uncertainties

I need to fit data points on a power law and each one of these carries an uncertainty. I've been using Python, more precisely scipy.optimize.curve_fit to get the job done but I don't know how to ...
0
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1answer
24 views

Is there a statistical differing interpretation between match and fit?

I've seen the terms matching/match and fitting/fit used almost interchangeably when discussing models goodness of fit, observed vs simulated data matching, etc. Is there a difference in ...
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0answers
14 views

Limiting the range of possible values for distribution fitting with GAMLSS in R

I'm trying to fit ST5 distribution for reaction times with GAMLSS. Sometimes mu parameter of the distribution is negative, which is implausible. Is it possible to limit the range of parameter values ...
0
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1answer
40 views

Regressing, analysing data with points rather than polynomial?

I am looking into making a regression of a bunch of data that is contained on some range of real numbers. In my case, x is between 0 and 1 and y is between 0 and 10. If I have 150 data points on this ...
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0answers
27 views

Fitting a straight line to components of complex numbers

I have a strange problem that I'm not sure how to solve: I have complex data points in a time series. The amplitude of these complex numbers in the time series forms a straight line, which I have fit ...
2
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0answers
18 views

Polynomial Data Fitting for Two Unknown Equation

I have a kind of data and want to find the equation(poly coeff) of given data. For example equation for given sample data is simple a^2*b+10 ...
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1answer
44 views

code for ordered probit model

I have a data set with 7 predictor variables and one dependent variable. The dependent variable has 4 categories so it's not binomial. I need to fit a probit model. I need codes for probit model in ...
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1answer
24 views

Comparing polynomials

I've got a bunch of data on pop singers' performance on the Hot 100 charts over time, and I'm trying to compare the early part of different artists' careers. For example, I might look compare Miley ...
3
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1answer
243 views

Determining probability distribution for datasets with missing values

As a part of my exploratory data analysis (EDA) prior to further analysis, I'm trying to determine a probability distribution of my pilot dataset's variables. A particular feature of this dataset is a ...
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2answers
493 views

What to do when CFA fit for multi-item scale is bad?

I am not sure how to proceed with this CFA im doing in lavaan. I have a sample of 172 participants (I know that’s not much for a CFA) and 28 items with 7-point Likert scales that should load on seven ...
0
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1answer
143 views

Fit measures for GMM Arellano-Bond estimator in R

A colleague and I have been working with difference GMM, i.e. the Arellano-Bond estimator, in R. Our option has been to use the pgmm command from the plm package. However, now I am struggling to test ...
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0answers
51 views

How can I use Akaike's Information Criterion to compare two models of multi-peaked emission spectra?

I have several photoluminescence emission spectra that I am trying to fit curves to. The spectra each have a slight baseline and four peaks. The independent variable $x_i$ is wavelength (converted to ...
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0answers
70 views

How to validate goodness of fit and forecasting quality of a model?

I am working on big data sets, which represent electricity consumption on power substation throughout the year. I have data every 10 minutes and multiple (and long) seasonalities. I have a daily, ...
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0answers
23 views

Retreiving Integrated Fitted Data from Stationary Fitted Data

Note that this is a simplified example: I have some time series that I made stationary by differencing twice. Then I ran arima on it, and set d = 0 to prevent ...
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0answers
13 views

Artificial distribution to best match an actual one

There's a problem I am struggling to solve, if anything because I can't find the right angle from which to attack it. It's basically a fitting problem, and possibly a topological one, although I'm not ...
4
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1answer
110 views

Model with non-linear transformation

I don't understand this concept well and need help. I was choosing whether to use a linear model or apply a non-linear transformation in my model formula. To do a diagnostic, I quickly plotted my ...
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2answers
78 views

How to make IPF code faster and more concise in R

Iterative proportional fitting is a way of adjusting 'internal cells' in a multidimensional matrix to optimise fit. It is also known as 'raking' and can be seen as a subset of 'entropy maximisation'. ...
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0answers
30 views

Applying Delta Method to generate prediction bands for custom distributions step by step

I think that this is an interesting issue for all those who whan to not only adjust one prediction function, but also to obtain the prediction bands to asses the graphical or tabular error I'm trying ...
0
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1answer
94 views

Errors when fitting a SARIMAX model in R

Currently working on big data sets, I would like to fit a SARIMAX model to it in order to forecast future values. Here are my questions : Q1. As a matter of information, does anybody know how does R ...
2
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0answers
40 views

How to approximate error on Chi-Squared Fit when bin counts are zero

I am using a galaxy image simulator that provides a 2D histogram that has the number of photons per pixel (bin) $N$. I am currently using a least-squares residual: $\sum_{bin}(f_{data}-f_{model})^2$ ...
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0answers
35 views

Estimating a distribution from a dataset with multiple parameters

How would you go about solving the following problem? You're an insurance company who writes workers compensation policies. You want to build a probability distribution for the number of annual ...
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0answers
40 views

Estimating Parameters of truncated generalized pareto distribution by probability weighted moments

Is it possible to estimate parameters for a truncated Generalized Pareto Distribution (Wikipedia Article) by probability weighted moments? If not, why is that so? I am aware that it would be possible ...
1
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1answer
131 views

Logistic Regression - Model Does not Fit

My name is Abhi and I am fairly new to statistics. I found some sample exercises online & I am trying to solve them to get a better understanding of model development. Problem Statement Assume ...
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3answers
131 views

Issues with fitting distribution to heavy-tailed data

I am currently trying to fit distributions to some heavy tailed data-set (see the data set below) and have a hard time producing good results: ...
0
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1answer
75 views

Estimating a distribution based on three percentiles and a mean

I have a set of percentiles the 10-th, 50-th and 90-th. Furthermore I have the mean value. I am trying to reconstruct the underlying distribution. The question is similar to Estimating a ...
2
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1answer
52 views

Finding analytic form for distributions using linear regression, need ideas

I'm trying to find an analytical form to describe these probability density functions: I'm pretty new to all of this, but think I should use some linear combination of basis functions (so I can then ...
3
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1answer
157 views

“Better” goodness-of-fit tests than chi squared for histogram modeling?

I work on data from a mass spectrometer that produces billions upon billions of count histograms, and I need a good way to test whether these histograms are consistent with one or several model ...
0
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1answer
51 views

Regression model for $f(x_1, x_2) = a + b x_1\log x_2$

Which regression algorithm do I need to use to fit the coefficients of $f(x_1, x_2) = a + b x_1\log x_2$? Will linear regression with an independent variable $x_1 \log x_2$ work?
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0answers
31 views

How to find out some particular distribution given the grouped data and a polynomial fitted to the data

I have to analyse a set of grouped data.The data is divided into groups by some categories for example: BP(<=60), BP((60,80]); Pulse(<75), Pulse((75,90]) & Pulse(>90) etc having many more ...
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0answers
140 views

Fitting for a Poisson-Gaussian Mixture Distribution

First of all, I am rather new to statistics, so go easy on me. I am aware that the negative binomial distribution can be thought to arise as a result of letting the $\lambda$ parameter in a Poisson ...
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0answers
17 views

How to incorporate a noise model into a probabilistic model?

Let's say have a probabilistic model $m$ which I fit to data using maximum likelihood. Now, I would like to add a noise model $n$ which I can also fit independently using maximum likelihood. So I am ...
2
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0answers
45 views

How to know one system is significantly better than another one?

I am studying lexical semantics. I have 65 pairs of synonyms with their sense relatedness. The dataset is derived from the paper: Rubenstein, Herbert, and John B. Goodenough. "Contextual correlates ...
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0answers
21 views

Finding the right parameter for a student's $t$-distribution

Suppose I have a homogeneous time series $x_n$, where the values arrive each second. For $n\ge 60$, let $\sigma_n$ be the standard deviation of the values $x_{n-59},\ldots,x_n$. Under the assumption ...
0
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1answer
62 views

fitted() function in R vs adding the residuals to the original data

I've found a discrepancy between the output of the fitted() function and adding the residuals to the original data set. Is the fitted() function not doing what I think it should be doing?
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2answers
62 views

How to show that there is no relationship

I have some data which I am using to show that there is no relationship between two variables. (Or only a weak one.) In a previous writeup, I included the scatterplot showing no visible relationship, ...
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1answer
30 views

Number of points crossed by their best fit line

My lab teacher asked this question in class, but i find no way to work it out. If I have $n$ points with their uncertainties, I know that they follow a linear expression and I find the best-fit line ...
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0answers
36 views

Bank loan model (spr?)

I am trying to fit a model investigating the amount of the loan (or a transformation of it) as a function of the the variables income, gender, customer and age. Fitting a standard linear regression ...